diff --git a/include/MedtechPrimaryGeneratorAction.hh b/include/MedtechPrimaryGeneratorAction.hh
index 9fddac3..13ec5a6 100644
--- a/include/MedtechPrimaryGeneratorAction.hh
+++ b/include/MedtechPrimaryGeneratorAction.hh
@@ -15,11 +15,13 @@
 #include "G4ParticleGun.hh"
 #include "G4ParticleTable.hh"
 #include "G4ThreeVector.hh"
+#include "Parameters.hh"
 
 class MedtechPrimaryGeneratorAction : public G4VUserPrimaryGeneratorAction
 {
 public:
     MedtechPrimaryGeneratorAction();
+    MedtechPrimaryGeneratorAction(int energy);
     virtual ~MedtechPrimaryGeneratorAction();
     virtual void GeneratePrimaries(G4Event* anEvent);
     
diff --git a/src/MedtechPrimaryGeneratorAction.cc b/src/MedtechPrimaryGeneratorAction.cc
index cefcee1..7fa79ae 100644
--- a/src/MedtechPrimaryGeneratorAction.cc
+++ b/src/MedtechPrimaryGeneratorAction.cc
@@ -9,6 +9,8 @@
 
 MedtechPrimaryGeneratorAction::MedtechPrimaryGeneratorAction()
 {
+    Parameters *param = Parameters::getInstance();
+    
     G4int numberOfParticles = 1;
     particleGun = new G4ParticleGun(numberOfParticles);
     G4ParticleTable *particleTable = G4ParticleTable::GetParticleTable();
@@ -16,7 +18,19 @@ MedtechPrimaryGeneratorAction::MedtechPrimaryGeneratorAction()
     particleGun -> SetParticleDefinition(particle);
     particleGun -> SetParticlePosition(G4ThreeVector(1,1,1));
     particleGun -> SetParticleMomentumDirection(G4ThreeVector(0, 0, 4*m));
-    particleGun -> SetParticleEnergy(6*MeV);
+    particleGun -> SetParticleEnergy(param -> GetParticleEnergy() *MeV);
+}
+
+MedtechPrimaryGeneratorAction::MedtechPrimaryGeneratorAction(int energy)
+{
+    G4int numberOfParticles = 1;
+    particleGun = new G4ParticleGun(numberOfParticles);
+    G4ParticleTable *particleTable = G4ParticleTable::GetParticleTable();
+    G4ParticleDefinition *particle = particleTable -> FindParticle("e-");
+    particleGun -> SetParticleDefinition(particle);
+    particleGun -> SetParticlePosition(G4ThreeVector(1,1,1));
+    particleGun -> SetParticleMomentumDirection(G4ThreeVector(0, 0, 4*m));
+    particleGun -> SetParticleEnergy(energy*MeV);
 }
 
 MedtechPrimaryGeneratorAction::~MedtechPrimaryGeneratorAction()